The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 60 |
| 4 | 497 |
| 5 | 4139 |
| 6 | 34440 |
| 7 | 286609 |
| 8 | 2385103 |
| 9 | 19848420 |
| 10 | 165175073 |
| 11 | 1374558131 |
| 12 | 11438832720 |
| 13 | 95191968481 |
| 14 | 792170939287 |
| 15 | 6592308228300 |
| 16 | 54860037930257 |
| 17 | 456535656023099 |
| 18 | 3799210009394520 |
| 19 | 31616362282015729 |
| 20 | 263105846077449823 |
| 21 | 2189520907644321780 |
| 22 | 18220810660362200513 |
[0,1,7,60,497,4139,34440,286609,2385103,19848420, 165175073,1374558131,11438832720,95191968481, 792170939287,6592308228300,54860037930257, 456535656023099,3799210009394520, 31616362282015729,263105846077449823, 2189520907644321780,18220810660362200513] |